The present invention relates to disk recording or playback devices, and more particularly to a device having a mechanism for preventing a disk from inadvertently moving away from a pickup during recording.
Devices are already known for use with a disk 6 rotatably encased in a cartridge 60 for recording or reproducing digital signals. FIG. 14 shows the principle of recording signals on the disk 6 which is in rotation in a horizontal plane. A magnetic field is applied by a recording head 72 to the disk 6 having a magnetic surface from the upper side thereof, and a laser beam is projected by a pickup 7 on the disk from therebelow. The portion of the disk 6 locally heated with the laser beam loses the coercive force when Curie temperature is reached (about 200xc2x0 C.), so that the heated portion is instantaneously magnetized by the recording head 72. When moving out of the laser beam with the rotation of the disk 6, the heated portion is cooled, whereby the direction of magnetization is fixed.
If the disk 6 inadvertently becomes raised during recording, moving away from the pickup 7, accurate signals are not recorded on the disk 6 since the laser beam is brought out of the proper position. Accordingly, there is a need to provide an expediency for preventing the disk 6 from inadvertently moving away from the pickup 7 during recording. The following expediency is used conventionally.
FIG. 10 is a perspective view of a conventional disk recording or playback device commercially available, and FIG. 11 is a side elevation showing a cabinet 2 of FIG. 10 only in section. Pivoted as at 91 to a chassis 1 within the cabinet 2 are a lid 8 and a base end of a holder 9 for accommodating the cartridge 60. The lid 8 and the holder 9 are pivotally movable together. Disposed inside the front wall of the cabinet 2 is a slide member 4 movable leftward or rightward. The slide member 4 is provided with a hook piece 40 engageable with the lid 8, and a knob 43 projecting forward through a slit 20 in the front wall of the cabinet 2. The slide member 4 is biased by a spring 42 in a direction for the hook piece 40 to engage with the lid 8. When the knob 43 is pushed by hand against the force of the spring 42, the hook piece 40 is disengaged from the lid 8.
The chassis 1 is provided with a restraining piece 5 retractably movable toward the slide member 4 by a drive mechanism (not shown).
Pivoted to the chassis 1 is a head lever 71 positioned on the holder 9 and carrying the recording head 72 on its forward end. The holder 9, with the cartridge 60 inserted therein, is lowered by pushing by hand, while the head lever 71 is lowered by a lift mechanism (not shown). The recording head 72 is brought into contact with the disk 6 to record signals thereon. The chassis 1 is attached to the cabinet 2 by cushion members 10 and made movable to and fro sideways relative to the cabinet 2, whereby vibration, shake or impact given to the cabinet 2 is prevented from acting directly on the chassis 1, precluding the head lever 71 from jumping.
For recording, the hook piece 40 of the slide member 4 engages with the lid 8 as seen in FIG. 12. At this time, the restraining piece 5 is moved toward the slide member 4 to fit the forward end of the piece into an opening 48 of the slide member 4. A clearance H (see FIG. 13) in the opening 48 alongside the restraining piece 5 serving as an allowance is smaller than an allowance provided for the engagement of the hook piece 40 with the lid 8, such that even if the user inadvertently pushes the knob 43 sideways by hand, the lid 8 will not be released from the hook piece 40. Since the lid 8 and the holder 9 do not open inadvertently during recording, the cartridge 60 will not move away from the pickup 7, ensuring a stabilized operation for recording signals on the disk 6.
The conventional device nevertheless has the following problem.
The restraining piece 5 is attached to the chassis 1, which is made movable to and fro within the cabinet 2 by the cushion members 10. If the clearance H is small in this case, the amount the chassis 1 is allowed to move to and fro sideways relative to the cabinet 2 is small. Accordingly, when the cabinet 2 is subjected to vibration or is shaken, the restraining piece 5 is liable to contact an edge of the opening portion 48, delivering the shake to the chassis 1 easily. Consequently, the head lever 71 jumps to result in an unstable recording operation, and the cushion members 10 provided become less effective. Further, if the clearance H is small, the chassis 1 needs to be installed in the cabinet 2 with high accuracy since errors are not allowable in positioning the chassis 1 relative to the cabinet 2.
Conversely, if the clearance H is great, the lid 8 is liable to become disengaged from the hook piece 40, permitting the lid 8 and the holder 9 to open inadvertently during recording. Thus, faults will occur if the clearance H is great or small.
An object of the present invention is to provide a device of the type described wherein the slide member is locked during recording of signals while permitting movement of the chassis and the restraining piece, with the slide member held in its locked position, when the device is subjected to external impact.
A slide member 4 engageable with and disengageable from a lid 8 as pivotally moved to a lowered position is provided with a latch member 3 having a wide pushable surface orthogonal to the direction of retractable movement of a restraining piece 5 and movable in the direction of retractable movement of the restraining piece 5.
The latch member 3 is movable between a locking position in which the latch member 3 is engaged with a cabinet 2 by being pushed by the restraining piece 5 to prevent the movement of the slide member 4 when signals are recorded on a disk and a standby position in which the latch member 3 is free from the pushing contact of the restraining piece 5 to permit the movement of the slide member 4 in a mode other than the recording. The restraining piece 5 and a chassis 1 are movable in the direction of movement of the slide member 4 within a range in which the restraining piece 5 is in pushing contact with the pushable surface of the latch member 3 in the locking position.
During recording of signals on the disk, the latch member 3 is in the locking position, i.e., in engagement with the cabinet 2 by being pushed by the restraining piece 5, preventing the movement of the slide member 4. To restrain the slide member 4 from moving by engaging the latch member 3 with the cabinet 2, the latch member 3 is held pushed toward the cabinet by the restraining piece 5.
Accordingly, the slide member 4 remains immovable even when the chassis 1 moves along the direction of movement of the slide member 4 within the range in which the restraining piece 5 is in pushing contact with the pushable surface of the latch member 3. While holding the latch member 3 pushed toward the cabinet 2, the restraining piece 5 and the chassis 1 are movable along the direction of movement of the slide member 4 with an allowance involved, and are allowed to move more greatly than in the conventional arrangement. Further the restraining piece 5 and the chassis 1 are allowed to move in a direction orthogonal to the direction of movement of the slide member 4 if the latch member 3 is in engagement with the cabinet 2. Thus, even if the cabinet 2 is shaken, the chassis 1 is free to move to and fro along the direction of movement of the slide member 4, i.e., leftward or rightward, or forward or backward. This diminishes the likelihood that the shake will be delivered to the chassis 1 to ensure a stabilized recording operation.
The chassis 1 is allowed to move to and fro greatly, with the latch member 3 in engagement with the cabinet 2, consequently ensuring a stabilized recording operation in spite of shaking that could occur, even if the engagement of the latch member 3 with the cabinet 2 involves a diminished clearance. When the clearance is thus reduced, the movement of the slide member 4 can be restrained reliably, obviating the likelihood of the lid 8 and the holder 9 opening inadvertently.
Further because the chassis 1 can be positioned relative to the cabinet 2 with a greater lateral allowance involved than conventionally, high accuracy will not be required in installing the chassis 1 in the cabinet 2.